Generator for use in speed-indicator systems



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Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

FRANK W. WOOD, F MONTCLAIR, NEWJERSEY, ASSIGNOR TO CHAS. CORY & SON, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

GENERATOR FOR USE IN SPEED-INDICATOR SYSTEMS.

Application led January 21, 1921. Serial No. 438,930.

To @ZZ 'whom t may cof/wem:

Be it known that I, FRANK W. iVooD, a citizen of the United States, and resident of Montclair, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Generators for Use in Speed-Indicator Systems, of which the following is a specification.

This invention relates to an electrical speed indicator system and more particularly to anindicator of the type in which the armature of the generator is electrically connected to a speed indicating instrument of the voltmeter type andhas special reference to the provision of an indicator in which the generator is provided with means for adapting it to a speed indicating instrument and for maintaining such adaptation.

In apparatus of the type referred to, the shaft of a generator is connected to a rotating element, the speed of which is desired to be measured, the armature of the generator being connected to a voltmeter calibrated to read directly in units of speed. If the generator is supplied with field magnets having a constant strength, the electrowhich will yield a constant magnetic field to the extent necessary in precision instruments. My invention therefore contemplates the provision of a generator of simple design in which the characteristics of the generator may be maintained constant to the extent necessary for precision work.

It has valso been found desirable to provide a generator which may be easily adapted to a voltmeter having a predetermined calibration, kthe characteristicsk of the generator being adjustable to fit the preconceived arrangement of the voltmeter. To provide such means in which the characteristics can be maintained constant during a long period of use is a further obvious desideratum.

The principal objects of my invention therefore include, besides the provisions of a generator of simple design in which the magnetic field operative on the armature coils is maintained constant, the provision of a speed indicator system in which the characteristics of the generator may be adjusted to fit the predetermined characteristics of the voltmeter; the further provision of such a system in which such characteristics may be maintained constant for a long period of use of the apparatus, the provision of a novel generator having a permanent magnet system, means being provided for compensating for the loss of magnetism of the permanent magnet, and the further provision of a speed indicator system having such a generator in which the active field may be microscopically adjusted with relation to the speed indicator for the purpose of providing a precision speed indicating instrument.

To theaccomplishment of the foregoing and such' other objects as may hereinafter appear, my invention consists in the elements and their relation one to the other, as hereinafter particularly described and sought to be defined in the claim, reference being had to the accompanying drawings which show a preferred embodiment of my invention and in which Figure 1 is a plan view of a s ecial generator used with the speed inc icating system, parts being shown in section and other parts being broken away to disclose the interior construction of the generator, and

Figure Qis an elevational view of the generator with the end cover removed.

The system includes a generator 5, and the lines 6 and 7 connected to the brushes of the generator are connected to a plurality of speed indicators not shown, which are placed at various points at which it is desired to read thespeed of a rota-ting shaft.

My generator of special design is shown in detail in Figures 1 and 2 of the drawings, the operative parts of the generator being housed in a casing 15 made, for example, of any composition metal, the said casing being provided with the end cover 16 removably mounted thereon, as shown clearly in the drawings. The casing 15 and the cover 16 are provided with bearings generally designated as 17 and 18 respectively, the armature shaft 19 being journalled in said bearings, bearings 17 and 18 being substantially similar, one of these bearings. being shown in detail and comprises bushing` 2O mounted on a boss 21 formed integrally with casing `15, as by means of bolts 22, the bushing 2O being internally threaded atone end to receive the correspondingly threaded bushing cap 23, the bushing andthe bushing cap both providing bearings for the armature shaft 19, a ball bearing casing2ll being mounted in said bushing, as clearly shown* in AtheY drawings.`r @n VVthe"arn'iature shaft-19 is'mounted the armature'25, shown herein as of thev drum type, the 'coils ofV the! armature beii'ig'con'nected to thecommuta-V tor26 also'mou'nted asy usual oni the `armature shaft 19'. Thebrushes 27 are mounted in brush holders 28 on` op'positesides 'of the commutator, the lbrushes being urged into contact l vwith 1 the lcommutatorf by means of springs 29.7 The vbr'us'li holders 28-are mount#4 ed on braclretfslSO, insulating blocksll Abeing provided betweenv the brush 'holders' and fthe brackets.

To provide ja generator of' simple design, involving relatively inexpensive parts and capable of easel ofmanuffactu're, my invention contemplatesth'e' use of `permanent mag- Y netsl for the field units and these magnets are shown as made upof v'a'series of laminatedplates 32' oined 'together by' laminated bars 33, the pole faces 34 of the plates being contoured in *the usual way to encircle? the armaturecoils. The'plates and bars maybe made, for' example, of soft iron capable of easy` magnetization,- thel ba-rsand' plates be'- ing 'magnetized to provide an lexcessive field over andabove thatfreqinred forV generative purposes.

For the-purpose of providing a generator-' which maybe adjustablyadaptedtovoltmeters' of' preconceived design an'dfor the purpose of maintaining suchf adaptability' and for theA further purpose' ofv compensating for the lossloff magnetism of the soft iron permanent magnets to maintain a consta'nt relation betweenithe'speed ofthe' ar'- mature shaft andthe generated E. M2 F., I provide aV magnetic shunt across the poles lof the n a'gnet, the 'reluctance of-'whichis made* rari-able to vary-'the flu'X*densityacrossy the poles'active through the arinature'coils. Tov this end' I have provided a shunt in the forni of an annular member 35,' this memberbeing made preferably of'soft iron, this annulusvbeingexternally threaded as at/Bffand adapted for rotative movement inar corre# spondingly threaded substantially semicircular holder 37`and a threadedlugjSS. The

annulus is capableof axial motion with respect to the polesofvthe magnet, rotationjof thejannulns in the threaded holder and'lug effecting the'necessary axial displacement; Means is provided for retaining the annulus in'any adjusted position,"such means conannulus is rotated kfor movementtowardthe r magnet poles, 'opposite i rotation of the annulus resulting: inf a larger'flux 'density' across the pole .i faces of`l the lmagnet andiA through the armaturecoils and. less f leakage` justment of" the generator? with 1 respect ttoy the voltmeter, the relation between ithe Involt-v meter and the generator' mayv be maintained:

constant, irrespective of' the loss'fofrmagnet-:-

isin of' the' permanent f'ma'gnet," sucht closs ibe-4v 90 ing compensated for'by 'adjustabilitylof they annulus awayfrom thepolesf'ofthe magnet: The magnet initially 'has Zani excessive'rma'g-f netic field over and:above-thatirequiredifor generative purposesfmany ofthellin'es of 95 fiux being dissipated across theshunt. lVithrf the loss of magn'eti'smioff the ma'gnet,"`the:l leakage across the' shunty is decreased byV movin'gtheL annulus away? from theeldr` poles, thel lines fofl fiuX 'activeV throughlthe-100 armature coils being ablev to 'bei maintainedy constant by thesefmeansiy The operation of my.'device',willxbe;ap'-V parent from the` above description .thereofv The E. MI generated Vvacross:'.thelines.ofi 105 thegenerator is, as is obvio'us,directly pro.-l portion-al to the' spe'edfofA thear-mature' 'sh'a'fft`,'. this speed being indicated `A atl Vany'ofthe i voltmeters directly inRgiPLMi- Tofadaptf the generator to any particular voltmeter.r1 thef shu'ntf provided by"the' annullus 36' is fadjustedto' an'dfrofromithe field pol-esuntil the' f desired cooperation isfeifected'. Due 'to f the threadedinterrelation between the shunt'f and the shunt holder a microscopic" adjustment'may be effected. If,-in the course of: time, the permanent magnet' loses some' of its magnetism, 4thef lossv is compensated er for by increasing the flux density activethrough the armaturecoilsbyincreasinglthefreduce l tancev of the shunt circuit, r this being"4 ef? fected` as describedf' above byY rotating .the annulu's away' fromithe' fieldl poles:-`

It will therefore be appa-rent thatf Y have 1 provided1 an improv'ed generatori` fori speed 125 indicating systems infwhichlthe character'-v istics of the generator may be adjusted to 'the'i preconceived characteristics of. i they voltmeter and -the' adjusted relation i between the two maintained, my novel generator for armature, said means comprising' a holder 15 including a substantially semi-circular threaded member surrounding the shaft of the armature and attached to the field magnet and a threaded lug, a complementally threaded annular shunt member rotatable 20 therein, and means carried by said lug for securing the shunt member in any adjusted position.

Signed at New York in the county of New York and State of New York this 19th 25 day of January, A. D. 1921.

FRANK lV. WOOD. 

